You probably won't find another cowl and, let's face it, spending $50+ for a Stan's cowl is not really a good idea for THIS plane. It really isn't very well made. Frankly, I've got one and it's a total piece of S--t.
My suggestion is to retrofit a Carl Goldberg Ultimate two piece cowl to fit your extra. I did the same for mine. The cowl is much cheaper to buy an looks good.
Menawhile ... one thing I know: I'll stay away from just about everything with the Hobbico name. Their stuff is simply inferior to other comparable brands.